Vacuum discharge vessel



May 8, 1934. w. DALLENBACH VACUUM DISCHARGE VESSEL Filed- June '10. 1930 enter: flw/ vba i Patented May 8, 1934 UNET This invention relates srATss PATENT oFFiic 1,957,993 VACUUM DISCHARGE VESSEL Walter Dallenbach, Zurich, Switzerland Application June 10,

In Germany 1 Claim.

to cooling systems for metal vacuum discharge vessels having a mercury cathode and at least one main anode.

The invention relates more particularly to such vacuum the upper part of the there is provided in mercury cathode a condensation chamber which receives the main portion of the mercury vapor issuing from the mercury cathode and wherein an opening for the passage of the arc is left between the condensation chamber and the chambersfor receiving the anodes. The object of the cooling system in the first place is to condense the mercury evaporated at the cathode and to lead away the loss of energy at temperatures which do not constitute a danger for the structure, for instance, the seals. Cooling mean temperatures are sufficient for the said purposes.

a view to ensuring a reliable valve 0nd place, with between 50 and 100 C.

In the secaction, the density of the mercury vapor in the vicinity of the main anodes For this purpose cooling mean are necessary.

than the first named The present invention must be kept low. temperatures lower consists in providing a closed upper cooling vessel which surrounds the upper part of the vacuum vessel with the condensation chamber and the anode chambers also a lower cooling vessel with a condensation wall which is opposite the anode chambers and the openings for the passage of the mercury vapor escaping ing for the passage of the the arc and with which through the openarc comes in contact.

The upper cooling vessel absorbs the heat of condensation of the mercury evaporated at the cathode and also the waste heat which is liberated in the vicinity of the cathode and the main anodes; these are the main parts of the waste energy. However, the portion of the stream of the mercury vapor escaping in the direction of the main anodes is essential for the mercury vapor pressure in the vicinity of the main anodes. If this vapor pressure increases, it will detrimentally affect the valve action, as already stated, and the vapor pressure will increase as the load on the vacuum discharge In the system accordin vessel becomes greater. g to the present invention, the portion of the stream comes in contact with the condensation wall of the lower cooling vessel whereby a re-evap takes place according to condensation wall. This oration of the mercury the temperature of the re-evaporation is only essential for the mercury vapor pressure in the .vicinity of the main ano des, which is therefore 1930, Serial No. 460,274

June 29, 1929 determined by the temperature of the lower cooling vessel.

A further object of the present invention consists in providing means whereby the lower vessel is kept at a lower temperature than the upper vessel. Two separate re-coolers are preferably used, one for the upper cooling vessel and the other for the lower cooling vessel. A common cooling medium pipe orcoil is provided for both re-coolers which conveys the liquid for re-cooling first through the re-cooler belonging to the lower cooling vessel and then through the other re-cooler. Consequently, the lower cooling vesselis thermally loaded to such a small extent that its temperature also increases to only a small eX- tent in the case of increasing load within the normal load limits. The mercury vapor pressure in the vicinity of the main anodes therefore remains always low sothat a reliable valve action is ensured.

In the accompanying description and in the drawing constituting a part of the present application and also in the accompanying claim, further details of the present invention are shown and described.

Figure 1 is a longitudinal section through a mercury vapor rectifier with cooling means according to the present invention; the section is on line I-I of Figure 2.

Figure 2 is a cross section on line Figure 1.

1 is the mercury cathode and 2 indicates the six main anodes of the rectifier. The auxiliary anodes are not shown. The vacuum vessel consists of two parts, an upper part and a lower part 9 which are connected together at 3, by welding or other means. Two plates 4 and 5, which cover the metal cylinder 6, the outer cylinder '7 and the six tubes 8 forming the anode arms are welded together to form a hollow body for containing the 5; cooling liquid. The cylinder 6 is closed at the top by the plate 5, and is open at the bottom and terminating by a flared part 9. The tubes 8 are open at the bottom and are closed at the top by the insulators 10, through which the an- 0 odes are led in. The lower part consists of the conical part 12, the plate 13 and the two cylindrical parts 14 and 15 together with the plate 4 form a hollow body for holding the cooling liquid.

In the plate 13 is a circular opening which is 5 closed by the cathode insulator 16 and the oathode 1. When the left hand anode is ignited, the arc will follow the path from 21 indicated by the broken line and the arrows.

The mercury evaporating from the cathode 1 110 II--II of 35:

is led through a chimney 17 into the hollow cylinder 6 and condenses on the walls of the latter. A portion of the stream of mercury escapes between the chimney 17 and the flared part 9 downwards. This portion will become greater, the higher the temperature of the cylinder becomes. The downwardly escaping mercury strikes against the cooled wall 12 and condenses. Reevaporation will take place at the cooled wall 12 in accordance with its temperature, which reevaporation determines the mercury vapour pressure in the vicinity of the main anodes 2. Both the hollow space in the upper part and the holl-ow space in the lower part contain an evaporating liquid. The liquid vapour formed by the heat is conveyed in the case of each cooler through a tube 18 or 19 respectively into the condensers 20 and 21 respectively and will condense on the cooling coils 22 and 23 through which water flows. The condensate flows back through the tubes 24 and 25 into the evaporators. The fresh water flows first through the cooling coil 22 and then through the cooling coil 23. The cooler in the lower part thus has a lower temperature than the cooler in the upper part. The cooler in the lower part will assume a temperature which is only slightly above the temperature of the entering water, for the arrangement of the two coolers is such that the cooler in the upper part has to lead away the greater part and the cooler in the lower part only a small quantity of the waste energy. The cathode is not cooled directly but by the evaporation of mercury. The greater part of the waste energy corresponding to the cathode drop thus passes with the mercury vapour to the cooler in the upper part. But the main part of the heat liberated at the main anodes and in their vicinity will be given off to the cooler in the upper part. The cooler in the lower part is thus relieved in a great degree by this arrangement and during a long interval between loads will retain a temperature only slightly above the temperature of the cooling water as it enters.

I claim:-

In a metallic vacuum discharge vessel, a body, a mercury cathode in said body, a condensation chamber in the upper part of the body above the mercury cathode receiving the main portion of the mercury vapor issuing from the cathode, anode chambers in said body, anodes in said chambers, said body having an opening for the passage of the arc from the condensation chamber to the anodes, a closed upper cooling chamber surrounding the upper part of the condensation chamber and the anode chambers adapted to condense the main portion of the mercury vapor, a closed lower cooling chamber separate from the first mentioned cooling chamber, said second cooling chamber including a cooling surface located opposite said opening, separate bodies of cooling liquid in the two cooling chambers, and means adapted to maintain the cooling liquid in the lower cooling chamber, at a lower temperature than that of the upper cooling chamber, the last mentioned means including separate cooling devices connected respectively with the upper and lower cooling chambers for maintaining a circulation of the cooling liquid therethrough, and a cooling conduit common to the two cooling devices for conducting a cooling agent therethrough, the cooling agent being conducted by said conduit first to the cooling device associated with the lower chamber and then to the cooling device associated with the upper cooling cham ber.

WALTER DALLENBACH. 

